Epigenetic Repression of eNOS in Scleroderma (SSc) Microvascular Endothelial Cells (MVECs) is Related to the Downregulation of MicroRNA-152 by Enhanced DNA Methyltransferase 1 (Dnmt1) Expression.

Objectives: Alteration in Scleroderma (SSc)-microvascular endothelial cells (MVEC) is related to epigenetic influences on gene expression level. Nitric oxide synthase gene (NOS3) repression is a prime example of epigenetic alteration of SSc-MVEC phenotype. The underlying mechanism of epigenetic imprinting in SSc-MVEC remains unknown. MicroRNAs (miRNAs), which are noncoding RNAs that regulate gene expression, are involved in diverse biological functions, including epigenetics regulation. It has been reported that downregulation of microRNA-152 induces aberrant DNA methylation by targeting the maintenance methyl transferase Dnmt1. In this study, we investigated miRNA-152 expression levels in SSc-MVEC and whether it is involved in the regulation of epigenetic imprinting in SSc. Methods: MVEC cells were isolated from skin biopsies of SSc patients and matched control subjects. The NOS3, Dnmt1, and miR-152 expression levels in normal and SSc-MVEC were checked by real-time PCR. The epigenetic regulation of NOS3 was examined by the addition of DNA methyltransferase and histone deacetylase inhibitors to MVEC cultures and by analysis of CpG site methylation in the NOS3 promotor